This invention relates to an assembly for facilitating the placement of a surgical knot made from a suture filament. In particular, the invention relates to such an assembly which is particularly adapted for deployment of the knot during minimally invasive surgical procedures where access to the surgical site is limited.
A mainstay of surgical practice has been and will continue to be the formation and placement of surgical knots from suture filament to fasten tissue during an operative procedure. Numerous surgical knots have been developed over an appreciable period of time, and the art of forming and tying knots for surgical applications is a critical skill which a surgeon must possess to perform an operation safely and efficiently. Accordingly, the art is extensively developed. See, for example, Tissue Approximation in Endoscopic Surgery, Alfred Cuschieri, Zoltan Szabo, Times Mirror International Publishers, 1995, which describes numerous surgical knots made from suture filament to facilitate the approximation of tissue during surgery.
The art of surgical knots is also well represented in the patent literature. U.S. Pat. No. 2,012,776 discloses a surgical instrument for facilitating the placement of various forms of slip knots made from surgical filament. The inventor named on the '776 patent, H. A. Roeder, developed the "Roeder Knot" which is a surgical knot which is frequently used in practice today. More recently, U.S. Pat. No. 5,573,286 discloses a surgical knot of suture strand particularly adapted for orthopedic applications. The preferred embodiment described in the '286 patent is directed to tying the knot to a bone.
Early on, it was recognized that the deployment and placement of surgical knots within a remotely accessible surgical site could be difficult, cumbersome and often unreliable. Accordingly, instrumentation was developed to facilitate the placement of knots in remote locations. Cleverly, a pre-tied knotted loop of suture was often used to reduce the number of steps required to form the tightened knot. For example, U.S. Pat. Nos. 2,566,625 and 3,090,386 describe surgical devices which are adapted to support a pre-tied knotted loop of suture for suturing or ligating tissue, particularly during procedures where the tissue desired to be manipulated is difficult to access.
More recently, instrumentation has been developed for facilitating the placement of knots particularly during minimally invasive surgical procedures. In particular, U.S. Pat. No. 5,320,629 discloses the formation of a pre-tied knotted loop of suture, and the placement of the pre-tied knotted loop on a surgical device for facilitating the tightening of the loop to approximate tissue during endoscopic surgical procedures. German Patent No. 912619 also discloses a device similar to that disclosed in the '629 patent.
Although the art of surgical knots is well developed, and surgical devices for facilitating the placement of tightened knots from a pre-tied knotted loop of suture have also been developed for application at remote surgical sites, there are problems which still need to be addressed. In particular, in those surgical procedures where access to the site is limited, for example during minimally invasive procedures such as endoscopic surgical procedures, the knots can be difficult to deploy. Frequently, the knots which can be deployed are routinely slip knots having poor knot security. If knot security is poor, then the approximated tissue may not be held for a sufficient period of time to promote adequate wound healing. Additionally, during minimally invasive procedures, the pre-tied knotted loops of suture which have been described in the prior art devices can be difficult to efficiently tighten for final deployment.
Therefore, in minimally invasive surgical procedures where access to the surgical site is limited, what is needed is an assembly for facilitating the formation of a surgical knot. The assembly should be relatively simple in construction and should be compatible with a partially tied surgical knot. The assembly should facilitate the conversion of the partially tied knot into a fully formed knot which can provide a consistently strong knot security each time the knot is placed to enable even an inexperienced surgeon to confidently and efficiently place a secure suture knot. Additionally, it would be desirable if it were possible to easily retrofit the assembly onto various surgical instruments, particularly endoscopic instruments, for ease of use of the assembly to place surgical knots. Finally, it would be helpful if it were possible to reload the assembly with a second partially tied knot following deployment of the first knot so that the assembly can be used to place multiple knots.
In addition, what is needed is a device to facilitate the loading of a suture cartridge assembly onto a surgical instrument. Specifically, what would advance the state of the surgical art would be a device which aids the surgeon to load the assembly onto a surgical instrument for deploying a surgical knot from the suture filament contained in the assembly, and to easily reload the instrument with a second suture cartridge assembly after the first spent assembly has been removed from the instrument. It would also be advantageous if such a device could be designed to avoid the need for the user to handle a needle when attached to the filament and to be a suitable container for shipping and storage of the suture cartridge when used in conjunction with the other packaging materials.
Further, in recognition of the need to facilitate knot tying endoscopically, what is also needed is an endoscopic instrument assembly which is capable of delivering the partially tied knot to the targeted anatomical structure within the internal body cavity during the endoscopic procedure. To that end, what is needed is an assembly which includes the knot tying instrument for efficient delivery through a trocar cannula. Specifically, it would be desirable if the suture filament and needle of the surgical knot tying instrument could be readily delivered through the cannula, without sacrificing or overly complicating the suture cartridge assembly or the resistance of the instrument to bending or tortial stresses incurred during use.